Multicolor writing instrument

ABSTRACT

A rotatably mounted, cylindrical cam groove member is formed on its peripheral surface with oppositely handed, helical cam grooves. A plurality of refill carriers are reciprocable in the axial direction of said cam groove member and in slidable engagement with respective ones of said cam grooves.

United States Patent Schumacher Oct. 7, 1975 [54] MULTICOLOR WRITING INSTRUMENT 2,264,463 l2/l94l Ttlmatsu 401/30 [75] n en o Emil Schumacher, Birkenfeld 2,579,887 12/1951 Vlerlmg 401/30 Germany FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Firma Sarastro Kinzinger GmbH, 272,588 12/1950 Switzerland 401/32 Pforzheim, Germany [22] Filed July 25 1974 Primary Examiner-Lawrence Charles 1. [21] App No 491,660 ABSTRACT [52] U S Cl 40160 A rotatably mounted, cylindrical cam groove member [51] 27/12 is formed on its peripheral surface with pp y [58] Field of Search 101/30 32 handed, helical cam grooves. A plurality of refill carriers are reciprocable in the axial direction of said cam [56] References Cited groove member and in slidable engagement with re- UNITED STATES PATENTS spective ones of said cam grooves.

1,981,917 11/1934 Kimura 401/30 12 Claims, 5 Drawing Figures US. Patent Oct. 7,1975 Sheet 1 01 2 3,910,705

Sheet 2 of 2 -s\\-\\\\k I 8 1. h 5 N US. Patent 0a. 7,1975

MULTICOLOR WRITING INSTRUIVIENT This invention relates to a color-changing multicolor writing instrument, particularly a ball point pen, which comprises a cam-controlled advancing and retracting mechanism.

Different advancing and retracting mechanisms are known for color-changing multicolor writing instruments. In writing instruments provided with such mechanisms, the advancing of another color refill causes the refill, which is then in writing position to be released and to be returned by spring action. A selected color refill may be advanced by means of sliders, which protrude from the shell of the writing instrument or by means of a pressure cap or through the intermediary of a color-selecting rocker. It is also known to advance the refills by means of a rotary cap and a cam sleeve, which acts on the heads of the refill carriers. When said sleeve is rotated, a refill carrier and the associated refill is moved to the advanced position against the action of a retracting spring. In all these embodiments it is difficult to design a slender writing instrument, which provides for an advancing stroke of adequate length and also to provide a mechanism, which can be assembled ready for being mounted in the instrument.

It is an object of the invention to provide a mechanism, which can be used in particularly slender writing instruments having a slender tip and providing for an v adequate advancing stroke, and also to provide for a mechanism, which can be assembled ready for insertion into the instrument. To accomplish that object, the color-changing multicolor writing instrument, particularly a ball point pen, is characterized according to the invention in that the refill carriers extend into oppositely handed, crossing helical cam grooves in a rotatably mounted cam groove member, the refill carriers have angle'd end fingers extend into the helical cam grooves on the rotatable cam groove member, and the end portions of the refill carriers are forwardly and rearwardly slidable in longitudinal slots of a guide sleeve, which is slidably fitted around the cam groove member. This arrangement results in a compact slender mechanism, which can inserted as a unit.

According to a further feature of the invention the cam groove member is rotatably mounted in the guide sleeve and under the action of a return-assisting spring, the force of which must be overcome as the cam groove member is advanced during the advance of one refill carrier while the second refill carrier engages the end of the guide slot. As a result, the advance of the first refill carrier is accelerated whereas the second refill carrier is relatively stationary.

Further details of the color-changing multicolor writing instrument according to the invention are shown diagrammatically and by way of example in the drawing, in which FIG. 1 is a central longitudinal sectional view showing the mechanism of the writing instrument,

FIG. 2 is a central longitudinal sectional view showing the mechanism of FIG. 1 after a rotation through 90,

FIG. 3 is an exploded view showing the components, and

FIGS. 4 and 5 are perspective views showing two different parts for guiding refill carriers.

As is apparent from the drawing, the color-changing multicolor writing instrument consists of a ball point pen and comprises a cam-controlled advancing and retracting mechanism. The latter comprises a rotatably mounted cam groove member 1, which is formed with oppositely handed, intersecting cam grooves 2, which receive angled rear end fingers 4 carried by the rear end portions 5 of the refill carriers 3. The rear end portions 5 are forwardly and rearwardly slidable in longitudinal slots 6 of a guide sleeve 7, which is fitted over the cam groove member 1. Instead of angled end fingers 4 as shown in FIG. 4, the refill carrier may be provided with a rear end portion 5a, which carries movably mounted, boat-shaped cam followers 4a, shown in FIG. 5, which are guided in the helical cam grooves 2.

The cam groove member 1 is rotatably mounted in the guide sleeve 7 and biased by the return-assisting spring 8, the action of which is overcome as the member 1 is advanced during the advance of one refill carrier 3 while the second refill carrier 3 engages the end of the associated longitudinal slot 6. As a result, the advance of the first refill carrier 3 is accelerated whereas the second refill carrier 3 is relatively stationary. The cam groove member 1 is provided at its rear end with an end pin 9, which extends through the guide sleeve 7 and into the adjoining sleeve 10, which contains the return spring. The pin has side flats 11 (FIGS. 2 and 3), by which the pin 9 is non-rotatably and longitudinally slidably connected to the sleeve 10. The returnassisting spring 8 surrounds the end pin 9 of the cam groove member 1 and bears at its rear end on the closinghead .12 and at its forward end on the inturned rim 13 of the sleeve 10 for the return-assisting spring. This is apparent from the sectional views. The rim 13 engages the side flats 11 to provide for a non-rotatable connection to the end pin 9.

As is also apparent, the sleeve 10 for the returnassisting spring is connected by screw threads 15 to a rotary knob 14 provided at the rear end of the writing instrument. The rotary knob my be replaced by an end cap 16 if the latter is rotatable. A rotation of the rotary knob 14 or of the end cap 16 is transmitted by the sleeve 10 and the end pin 9 to the cam groove member 1 so that the angled end finger 4 or cam follower 4a of one refill carrier 3 slides in the helical cam grooves 2, the end portion 5 of the refill carrier 3 slides in the longitudinal slots 6 of the stationary guide sleeve 7, and the cam groove member 1 is advanced or retracted as it is rotated to advance or retract a refill carrier. As described hereinbefore, the cam groove member 1 advances against the action of the spring 8, as described hereinbefore so that the advance or retraction of the refill carrier 3 is increased and the writing instrument may have a slender tapering tip portion, which is not shown here.

Finally, the guide sleeve 7 containing the cam groove member 1 is fitted in or connected by screw threads 18 to a mechanism sleeve 17, which surrounds the refill carrier end portions 5, and which is installed in a forward shell 19 of the writing instrument. In the present embodiment, the non-rotatable end cap is fitted on the shell 19 and surrounds the mechanism sleeve 17. As has been described, the rotary color-changing member consists of the rotary knob 14.

What is claimed is:

1. In a color-changing multicolor writing instrument of the type containing a rotatable, cylindrical cam groove member with oppositely threaded crossing helical cam grooves disposed on the periphery thereof and a plurality of refill carriers having end portions which engage said cam grooves;

the improvement consisting of providing a guide sleeve with two axially extending longitudinal slots, each of said slots defining a-channel in which said end portions ride, the ends of each of said channels defining the limits of axial movement of each of said end portions, said improvement further consisting of said cam groove member being disposed for limited axial movement, a return spring biased against the axial movement of the cam groove members so that when one of said end portions is engaged by the ends of one of said slots, said cam groove member is advanced axially against said bias.

2. A writing instrument as set forth in claim 1, in which said refill carriers carry ball point pen refills in different colors.

3. A writing instrument as set forth in claim 1, in which each of said end portions is provided with an angled end finger, which is in slidable engagement with one of said cam grooves.

4. A writing instrument as set forth in claim 1 in which each of said end portions carries a boat-shaped cam follower, which is in slidable engagement with one of said cam grooves.

5. A writing instrument as set forth in claim 1, in which said return-assisting spring is surrounded by a cylindrical spring sleeve and said guide sleeve is provided with a rear end pin,

which extends into said spring sleeve and is formed with side flats, which engage mating portions of said spring sleeve so that said sleeves are non rotatably connected and axially slidable relative to each other.

6. A writing instrument as set forth in claim 5, in which said rear end pin has an enlarged head at its rear end,

said spring sleeve has at its forward end an inturned rim formed with said mating portions, and

said return-assisting spring is a compression spring,

which surrounds said rear end pin and bears on said head and said inturned rim.

7. A writing instrument as set forth in claim 5, in

which manually rotatable means for rotating said cam groove member are provided at the rear end of said writing instrument and said spring sleeve is connected to said manually rotatable means.

8. A writing instrument as set forth in claim 7, in

which said spring sleeve is screw-threadedly connected to said manually rotatable means.

9. A writing instrument as set forth in claim 7, in

which said manually rotatable means comprise a rotary knob.

10. A writing instrument as set forth in claim 7, which comprises an end cap constituting said manually rotatable means.

1 l. A writing instrument as set forth in claim 1, which comprises an outer shell and a mechanism sleeve fitted in said outer shell,

said guide sleeve being fixed in said mechanism sleeve.

12. A color-changing mechanism for use in a colorchanging multicolor writing instrument, which comprises a guide sleeve having two axially extending longitudinal slots,

a cylindrical cam groove member formed on its peripheral surface with two oppositely handed, crossing helical grooves and rotatably and axially slidably mounted in said guide sleeve,

two refill carriers having rear end portions, which extend in respective ones of said slots and are axially slidable therein and in slidable engagement with respective ones of said cam grooves,

stop means, which are axially immovable relative to said sleeve and limit the rearward movement of each of said end portions in the associated slot,

manually rotatable means non-rotatably connected to said cam groove member and operable to rotate the same relative to said guide sleeve, and

a return-assisting spring, which urges said cam groove member in a rearward axial direction relative to said guide sleeve. 

1. In a color-changing multicolor writing instrument of the type containing a rotatable, cylindrical cam groove member with oppositely threaded crossing helical cam grooves disposed on the periphery thereof and a plurality of refill carriers having end portions which engage said cam grooves; the improvement consisting of providing a guide sleeve with two axially extending longitudinal slots, each of said slots defining a channel in which said end portions ride, the ends of each of said channels defining the limits of axial movement of each of said end portions, said improvement further consisting of said cam groove member being disposed For limited axial movement, a return spring biased against the axial movement of the cam groove members so that when one of said end portions is engaged by the ends of one of said slots, said cam groove member is advanced axially against said bias.
 2. A writing instrument as set forth in claim 1, in which said refill carriers carry ball point pen refills in different colors.
 3. A writing instrument as set forth in claim 1, in which each of said end portions is provided with an angled end finger, which is in slidable engagement with one of said cam grooves.
 4. A writing instrument as set forth in claim 1 in which each of said end portions carries a boat-shaped cam follower, which is in slidable engagement with one of said cam grooves.
 5. A writing instrument as set forth in claim 1, in which said return-assisting spring is surrounded by a cylindrical spring sleeve and said guide sleeve is provided with a rear end pin, which extends into said spring sleeve and is formed with side flats, which engage mating portions of said spring sleeve so that said sleeves are non-rotatably connected and axially slidable relative to each other.
 6. A writing instrument as set forth in claim 5, in which said rear end pin has an enlarged head at its rear end, said spring sleeve has at its forward end an inturned rim formed with said mating portions, and said return-assisting spring is a compression spring, which surrounds said rear end pin and bears on said head and said inturned rim.
 7. A writing instrument as set forth in claim 5, in which manually rotatable means for rotating said cam groove member are provided at the rear end of said writing instrument and said spring sleeve is connected to said manually rotatable means.
 8. A writing instrument as set forth in claim 7, in which said spring sleeve is screw-threadedly connected to said manually rotatable means.
 9. A writing instrument as set forth in claim 7, in which said manually rotatable means comprise a rotary knob.
 10. A writing instrument as set forth in claim 7, which comprises an end cap constituting said manually rotatable means.
 11. A writing instrument as set forth in claim 1, which comprises an outer shell and a mechanism sleeve fitted in said outer shell, said guide sleeve being fixed in said mechanism sleeve.
 12. A color-changing mechanism for use in a color-changing multicolor writing instrument, which comprises a guide sleeve having two axially extending longitudinal slots, a cylindrical cam groove member formed on its peripheral surface with two oppositely handed, crossing helical grooves and rotatably and axially slidably mounted in said guide sleeve, two refill carriers having rear end portions, which extend in respective ones of said slots and are axially slidable therein and in slidable engagement with respective ones of said cam grooves, stop means, which are axially immovable relative to said sleeve and limit the rearward movement of each of said end portions in the associated slot, manually rotatable means non-rotatably connected to said cam groove member and operable to rotate the same relative to said guide sleeve, and a return-assisting spring, which urges said cam groove member in a rearward axial direction relative to said guide sleeve. 